1 | /* Infrastructure for tracking user variable locations and values |
2 | throughout compilation. |
3 | Copyright (C) 2010-2023 Free Software Foundation, Inc. |
4 | Contributed by Alexandre Oliva <aoliva@redhat.com>. |
5 | |
6 | This file is part of GCC. |
7 | |
8 | GCC is free software; you can redistribute it and/or modify it under |
9 | the terms of the GNU General Public License as published by the Free |
10 | Software Foundation; either version 3, or (at your option) any later |
11 | version. |
12 | |
13 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or |
15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
16 | for more details. |
17 | |
18 | You should have received a copy of the GNU General Public License |
19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ |
21 | |
22 | #include "config.h" |
23 | #include "system.h" |
24 | #include "coretypes.h" |
25 | #include "backend.h" |
26 | #include "rtl.h" |
27 | #include "df.h" |
28 | #include "valtrack.h" |
29 | #include "regs.h" |
30 | #include "memmodel.h" |
31 | #include "emit-rtl.h" |
32 | #include "rtl-iter.h" |
33 | |
34 | /* gen_lowpart_no_emit hook implementation for DEBUG_INSNs. In DEBUG_INSNs, |
35 | all lowpart SUBREGs are valid, despite what the machine requires for |
36 | instructions. */ |
37 | |
38 | static rtx |
39 | gen_lowpart_for_debug (machine_mode mode, rtx x) |
40 | { |
41 | rtx result = gen_lowpart_if_possible (mode, x); |
42 | if (result) |
43 | return result; |
44 | |
45 | if (GET_MODE (x) != VOIDmode) |
46 | return gen_rtx_raw_SUBREG (mode, x, |
47 | subreg_lowpart_offset (mode, GET_MODE (x))); |
48 | |
49 | return NULL_RTX; |
50 | } |
51 | |
52 | /* Replace auto-increment addressing modes with explicit operations to access |
53 | the same addresses without modifying the corresponding registers. */ |
54 | |
55 | static rtx |
56 | cleanup_auto_inc_dec (rtx src, machine_mode mem_mode ATTRIBUTE_UNUSED) |
57 | { |
58 | rtx x = src; |
59 | |
60 | const RTX_CODE code = GET_CODE (x); |
61 | int i; |
62 | const char *fmt; |
63 | |
64 | switch (code) |
65 | { |
66 | case REG: |
67 | CASE_CONST_ANY: |
68 | case SYMBOL_REF: |
69 | case CODE_LABEL: |
70 | case PC: |
71 | case SCRATCH: |
72 | /* SCRATCH must be shared because they represent distinct values. */ |
73 | return x; |
74 | case CLOBBER: |
75 | /* Share clobbers of hard registers, but do not share pseudo reg |
76 | clobbers or clobbers of hard registers that originated as pseudos. |
77 | This is needed to allow safe register renaming. */ |
78 | if (REG_P (XEXP (x, 0)) && REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER |
79 | && ORIGINAL_REGNO (XEXP (x, 0)) == REGNO (XEXP (x, 0))) |
80 | return x; |
81 | break; |
82 | |
83 | case CONST: |
84 | if (shared_const_p (x)) |
85 | return x; |
86 | break; |
87 | |
88 | case MEM: |
89 | mem_mode = GET_MODE (x); |
90 | break; |
91 | |
92 | case PRE_INC: |
93 | case PRE_DEC: |
94 | { |
95 | gcc_assert (mem_mode != VOIDmode && mem_mode != BLKmode); |
96 | poly_int64 offset = GET_MODE_SIZE (mode: mem_mode); |
97 | if (code == PRE_DEC) |
98 | offset = -offset; |
99 | return gen_rtx_PLUS (GET_MODE (x), |
100 | cleanup_auto_inc_dec (XEXP (x, 0), mem_mode), |
101 | gen_int_mode (offset, GET_MODE (x))); |
102 | } |
103 | |
104 | case POST_INC: |
105 | case POST_DEC: |
106 | case PRE_MODIFY: |
107 | case POST_MODIFY: |
108 | return cleanup_auto_inc_dec (src: code == PRE_MODIFY |
109 | ? XEXP (x, 1) : XEXP (x, 0), |
110 | mem_mode); |
111 | |
112 | default: |
113 | break; |
114 | } |
115 | |
116 | /* Copy the various flags, fields, and other information. We assume |
117 | that all fields need copying, and then clear the fields that should |
118 | not be copied. That is the sensible default behavior, and forces |
119 | us to explicitly document why we are *not* copying a flag. */ |
120 | x = shallow_copy_rtx (x); |
121 | |
122 | /* We do not copy FRAME_RELATED for INSNs. */ |
123 | if (INSN_P (x)) |
124 | RTX_FLAG (x, frame_related) = 0; |
125 | |
126 | fmt = GET_RTX_FORMAT (code); |
127 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) |
128 | if (fmt[i] == 'e') |
129 | XEXP (x, i) = cleanup_auto_inc_dec (XEXP (x, i), mem_mode); |
130 | else if (fmt[i] == 'E' || fmt[i] == 'V') |
131 | { |
132 | int j; |
133 | XVEC (x, i) = rtvec_alloc (XVECLEN (x, i)); |
134 | for (j = 0; j < XVECLEN (x, i); j++) |
135 | XVECEXP (x, i, j) |
136 | = cleanup_auto_inc_dec (XVECEXP (src, i, j), mem_mode); |
137 | } |
138 | |
139 | return x; |
140 | } |
141 | |
142 | /* Auxiliary data structure for propagate_for_debug_stmt. */ |
143 | |
144 | struct rtx_subst_pair |
145 | { |
146 | rtx to; |
147 | bool adjusted; |
148 | rtx_insn *insn; |
149 | }; |
150 | |
151 | /* DATA points to an rtx_subst_pair. Return the value that should be |
152 | substituted. */ |
153 | |
154 | static rtx |
155 | propagate_for_debug_subst (rtx from, const_rtx old_rtx, void *data) |
156 | { |
157 | struct rtx_subst_pair *pair = (struct rtx_subst_pair *)data; |
158 | |
159 | if (!rtx_equal_p (from, old_rtx)) |
160 | return NULL_RTX; |
161 | if (!pair->adjusted) |
162 | { |
163 | pair->adjusted = true; |
164 | pair->to = cleanup_auto_inc_dec (src: pair->to, VOIDmode); |
165 | pair->to = make_compound_operation (pair->to, SET); |
166 | /* Avoid propagation from growing DEBUG_INSN expressions too much. */ |
167 | int cnt = 0; |
168 | subrtx_iterator::array_type array; |
169 | FOR_EACH_SUBRTX (iter, array, pair->to, ALL) |
170 | if (REG_P (*iter) && ++cnt > 1) |
171 | { |
172 | rtx dval = make_debug_expr_from_rtl (old_rtx); |
173 | rtx to = pair->to; |
174 | if (volatile_insn_p (to)) |
175 | to = gen_rtx_UNKNOWN_VAR_LOC (); |
176 | /* Emit a debug bind insn. */ |
177 | rtx bind |
178 | = gen_rtx_VAR_LOCATION (GET_MODE (old_rtx), |
179 | DEBUG_EXPR_TREE_DECL (dval), to, |
180 | VAR_INIT_STATUS_INITIALIZED); |
181 | rtx_insn *bind_insn = emit_debug_insn_before (bind, pair->insn); |
182 | df_insn_rescan (bind_insn); |
183 | pair->to = dval; |
184 | break; |
185 | } |
186 | return pair->to; |
187 | } |
188 | return copy_rtx (pair->to); |
189 | } |
190 | |
191 | /* Replace all the occurrences of DEST with SRC in DEBUG_INSNs between INSN |
192 | and LAST, not including INSN, but including LAST. Also stop at the end |
193 | of THIS_BASIC_BLOCK. */ |
194 | |
195 | void |
196 | propagate_for_debug (rtx_insn *insn, rtx_insn *last, rtx dest, rtx src, |
197 | basic_block this_basic_block) |
198 | { |
199 | rtx_insn *next, *end = NEXT_INSN (BB_END (this_basic_block)); |
200 | rtx loc; |
201 | rtx (*saved_rtl_hook_no_emit) (machine_mode, rtx); |
202 | |
203 | struct rtx_subst_pair p; |
204 | p.to = src; |
205 | p.adjusted = false; |
206 | p.insn = NEXT_INSN (insn); |
207 | |
208 | next = NEXT_INSN (insn); |
209 | last = NEXT_INSN (insn: last); |
210 | saved_rtl_hook_no_emit = rtl_hooks.gen_lowpart_no_emit; |
211 | rtl_hooks.gen_lowpart_no_emit = gen_lowpart_for_debug; |
212 | while (next != last && next != end) |
213 | { |
214 | insn = next; |
215 | next = NEXT_INSN (insn); |
216 | if (DEBUG_BIND_INSN_P (insn)) |
217 | { |
218 | loc = simplify_replace_fn_rtx (INSN_VAR_LOCATION_LOC (insn), |
219 | dest, fn: propagate_for_debug_subst, &p); |
220 | if (loc == INSN_VAR_LOCATION_LOC (insn)) |
221 | continue; |
222 | if (volatile_insn_p (loc)) |
223 | loc = gen_rtx_UNKNOWN_VAR_LOC (); |
224 | INSN_VAR_LOCATION_LOC (insn) = loc; |
225 | df_insn_rescan (insn); |
226 | } |
227 | } |
228 | rtl_hooks.gen_lowpart_no_emit = saved_rtl_hook_no_emit; |
229 | } |
230 | |
231 | /* Initialize DEBUG to an empty list, and clear USED, if given. */ |
232 | |
233 | void |
234 | dead_debug_global_init (struct dead_debug_global *debug, bitmap used) |
235 | { |
236 | debug->used = used; |
237 | debug->htab = NULL; |
238 | if (used) |
239 | bitmap_clear (used); |
240 | } |
241 | |
242 | /* Initialize DEBUG to an empty list, and clear USED, if given. Link |
243 | back to GLOBAL, if given, and bring in used bits from it. */ |
244 | |
245 | void |
246 | dead_debug_local_init (struct dead_debug_local *debug, bitmap used, |
247 | struct dead_debug_global *global) |
248 | { |
249 | if (!used && global && global->used) |
250 | used = BITMAP_ALLOC (NULL); |
251 | |
252 | debug->head = NULL; |
253 | debug->global = global; |
254 | debug->used = used; |
255 | debug->to_rescan = NULL; |
256 | |
257 | if (used) |
258 | { |
259 | if (global && global->used) |
260 | bitmap_copy (used, global->used); |
261 | else |
262 | bitmap_clear (used); |
263 | } |
264 | } |
265 | |
266 | /* Locate the entry for REG in GLOBAL->htab. */ |
267 | |
268 | static dead_debug_global_entry * |
269 | dead_debug_global_find (struct dead_debug_global *global, rtx reg) |
270 | { |
271 | dead_debug_global_entry temp_entry; |
272 | temp_entry.reg = reg; |
273 | |
274 | dead_debug_global_entry *entry = global->htab->find (value: &temp_entry); |
275 | gcc_checking_assert (entry && entry->reg == temp_entry.reg); |
276 | |
277 | return entry; |
278 | } |
279 | |
280 | /* Insert an entry mapping REG to DTEMP in GLOBAL->htab. */ |
281 | |
282 | static dead_debug_global_entry * |
283 | dead_debug_global_insert (struct dead_debug_global *global, rtx reg, rtx dtemp) |
284 | { |
285 | dead_debug_global_entry temp_entry; |
286 | temp_entry.reg = reg; |
287 | temp_entry.dtemp = dtemp; |
288 | |
289 | if (!global->htab) |
290 | global->htab = new hash_table<dead_debug_hash_descr> (31); |
291 | |
292 | dead_debug_global_entry **slot = global->htab->find_slot (value: &temp_entry, |
293 | insert: INSERT); |
294 | gcc_checking_assert (!*slot); |
295 | *slot = XNEW (dead_debug_global_entry); |
296 | **slot = temp_entry; |
297 | return *slot; |
298 | } |
299 | |
300 | /* If UREGNO, referenced by USE, is a pseudo marked as used in GLOBAL, |
301 | replace it with a USE of the debug temp recorded for it, and |
302 | return TRUE. Otherwise, just return FALSE. |
303 | |
304 | If PTO_RESCAN is given, instead of rescanning modified INSNs right |
305 | away, add their UIDs to the bitmap, allocating one of *PTO_RESCAN |
306 | is NULL. */ |
307 | |
308 | static bool |
309 | dead_debug_global_replace_temp (struct dead_debug_global *global, |
310 | df_ref use, unsigned int uregno, |
311 | bitmap *pto_rescan) |
312 | { |
313 | if (!global || uregno < FIRST_PSEUDO_REGISTER |
314 | || !global->used |
315 | || !REG_P (*DF_REF_REAL_LOC (use)) |
316 | || REGNO (*DF_REF_REAL_LOC (use)) != uregno |
317 | || !bitmap_bit_p (global->used, uregno)) |
318 | return false; |
319 | |
320 | dead_debug_global_entry *entry |
321 | = dead_debug_global_find (global, reg: *DF_REF_REAL_LOC (use)); |
322 | gcc_checking_assert (GET_CODE (entry->reg) == REG |
323 | && REGNO (entry->reg) == uregno); |
324 | |
325 | if (!entry->dtemp) |
326 | return true; |
327 | |
328 | *DF_REF_REAL_LOC (use) = entry->dtemp; |
329 | if (!pto_rescan) |
330 | df_insn_rescan (DF_REF_INSN (use)); |
331 | else |
332 | { |
333 | if (!*pto_rescan) |
334 | *pto_rescan = BITMAP_ALLOC (NULL); |
335 | bitmap_set_bit (*pto_rescan, INSN_UID (DF_REF_INSN (use))); |
336 | } |
337 | |
338 | return true; |
339 | } |
340 | |
341 | /* Reset all debug uses in HEAD, and clear DEBUG->to_rescan bits of |
342 | each reset insn. DEBUG is not otherwise modified. If HEAD is |
343 | DEBUG->head, DEBUG->head will be set to NULL at the end. |
344 | Otherwise, entries from DEBUG->head that pertain to reset insns |
345 | will be removed, and only then rescanned. */ |
346 | |
347 | static void |
348 | dead_debug_reset_uses (struct dead_debug_local *debug, |
349 | struct dead_debug_use *head) |
350 | { |
351 | bool got_head = (debug->head == head); |
352 | bitmap rescan; |
353 | struct dead_debug_use **tailp = &debug->head; |
354 | struct dead_debug_use *cur; |
355 | bitmap_iterator bi; |
356 | unsigned int uid; |
357 | |
358 | if (got_head) |
359 | rescan = NULL; |
360 | else |
361 | rescan = BITMAP_ALLOC (NULL); |
362 | |
363 | while (head) |
364 | { |
365 | struct dead_debug_use *next = head->next; |
366 | rtx_insn *insn; |
367 | |
368 | insn = DF_REF_INSN (head->use); |
369 | if (!next || DF_REF_INSN (next->use) != insn) |
370 | { |
371 | INSN_VAR_LOCATION_LOC (insn) = gen_rtx_UNKNOWN_VAR_LOC (); |
372 | if (got_head) |
373 | df_insn_rescan_debug_internal (insn); |
374 | else |
375 | bitmap_set_bit (rescan, INSN_UID (insn)); |
376 | if (debug->to_rescan) |
377 | bitmap_clear_bit (debug->to_rescan, INSN_UID (insn)); |
378 | } |
379 | XDELETE (head); |
380 | head = next; |
381 | } |
382 | |
383 | if (got_head) |
384 | { |
385 | debug->head = NULL; |
386 | return; |
387 | } |
388 | |
389 | while ((cur = *tailp)) |
390 | if (bitmap_bit_p (rescan, INSN_UID (DF_REF_INSN (cur->use)))) |
391 | { |
392 | *tailp = cur->next; |
393 | XDELETE (cur); |
394 | } |
395 | else |
396 | tailp = &cur->next; |
397 | |
398 | EXECUTE_IF_SET_IN_BITMAP (rescan, 0, uid, bi) |
399 | { |
400 | struct df_insn_info *insn_info = DF_INSN_UID_SAFE_GET (uid); |
401 | if (insn_info) |
402 | df_insn_rescan_debug_internal (insn_info->insn); |
403 | } |
404 | |
405 | BITMAP_FREE (rescan); |
406 | } |
407 | |
408 | /* Promote pending local uses of pseudos in DEBUG to global |
409 | substitutions. Uses of non-pseudos are left alone for |
410 | resetting. */ |
411 | |
412 | static void |
413 | dead_debug_promote_uses (struct dead_debug_local *debug) |
414 | { |
415 | for (struct dead_debug_use *head = debug->head, **headp = &debug->head; |
416 | head; head = *headp) |
417 | { |
418 | rtx reg = *DF_REF_REAL_LOC (head->use); |
419 | df_ref ref; |
420 | dead_debug_global_entry *entry; |
421 | |
422 | if (GET_CODE (reg) != REG |
423 | || REGNO (reg) < FIRST_PSEUDO_REGISTER) |
424 | { |
425 | headp = &head->next; |
426 | continue; |
427 | } |
428 | |
429 | if (!debug->global->used) |
430 | debug->global->used = BITMAP_ALLOC (NULL); |
431 | |
432 | bool added = bitmap_set_bit (debug->global->used, REGNO (reg)); |
433 | gcc_checking_assert (added); |
434 | |
435 | entry = dead_debug_global_insert (global: debug->global, reg, |
436 | dtemp: make_debug_expr_from_rtl (reg)); |
437 | |
438 | gcc_checking_assert (entry->dtemp); |
439 | |
440 | /* Tentatively remove the USE from the list. */ |
441 | *headp = head->next; |
442 | |
443 | if (!debug->to_rescan) |
444 | debug->to_rescan = BITMAP_ALLOC (NULL); |
445 | |
446 | for (ref = DF_REG_USE_CHAIN (REGNO (reg)); ref; |
447 | ref = DF_REF_NEXT_REG (ref)) |
448 | if (DEBUG_INSN_P (DF_REF_INSN (ref))) |
449 | { |
450 | if (!dead_debug_global_replace_temp (global: debug->global, use: ref, |
451 | REGNO (reg), |
452 | pto_rescan: &debug->to_rescan)) |
453 | { |
454 | rtx_insn *insn = DF_REF_INSN (ref); |
455 | INSN_VAR_LOCATION_LOC (insn) = gen_rtx_UNKNOWN_VAR_LOC (); |
456 | bitmap_set_bit (debug->to_rescan, INSN_UID (insn)); |
457 | } |
458 | } |
459 | |
460 | for (ref = DF_REG_DEF_CHAIN (REGNO (reg)); ref; |
461 | ref = DF_REF_NEXT_REG (ref)) |
462 | if (!dead_debug_insert_temp (debug, REGNO (reg), DF_REF_INSN (ref), |
463 | DEBUG_TEMP_BEFORE_WITH_VALUE)) |
464 | { |
465 | rtx bind; |
466 | bind = gen_rtx_VAR_LOCATION (GET_MODE (reg), |
467 | DEBUG_EXPR_TREE_DECL (entry->dtemp), |
468 | gen_rtx_UNKNOWN_VAR_LOC (), |
469 | VAR_INIT_STATUS_INITIALIZED); |
470 | rtx_insn *insn = emit_debug_insn_before (bind, DF_REF_INSN (ref)); |
471 | bitmap_set_bit (debug->to_rescan, INSN_UID (insn)); |
472 | } |
473 | |
474 | entry->dtemp = NULL; |
475 | XDELETE (head); |
476 | } |
477 | } |
478 | |
479 | /* Reset all debug insns with pending uses. Release the bitmap in it, |
480 | unless it is USED. USED must be the same bitmap passed to |
481 | dead_debug_local_init. */ |
482 | |
483 | void |
484 | dead_debug_local_finish (struct dead_debug_local *debug, bitmap used) |
485 | { |
486 | if (debug->global) |
487 | dead_debug_promote_uses (debug); |
488 | |
489 | if (debug->used != used) |
490 | BITMAP_FREE (debug->used); |
491 | |
492 | dead_debug_reset_uses (debug, head: debug->head); |
493 | |
494 | if (debug->to_rescan) |
495 | { |
496 | bitmap_iterator bi; |
497 | unsigned int uid; |
498 | |
499 | EXECUTE_IF_SET_IN_BITMAP (debug->to_rescan, 0, uid, bi) |
500 | { |
501 | struct df_insn_info *insn_info = DF_INSN_UID_SAFE_GET (uid); |
502 | if (insn_info) |
503 | df_insn_rescan (insn_info->insn); |
504 | } |
505 | BITMAP_FREE (debug->to_rescan); |
506 | } |
507 | } |
508 | |
509 | /* Release GLOBAL->used unless it is the same as USED. Release the |
510 | mapping hash table if it was initialized. */ |
511 | |
512 | void |
513 | dead_debug_global_finish (struct dead_debug_global *global, bitmap used) |
514 | { |
515 | if (global->used != used) |
516 | BITMAP_FREE (global->used); |
517 | |
518 | delete global->htab; |
519 | global->htab = NULL; |
520 | } |
521 | |
522 | /* Add USE to DEBUG, or substitute it right away if it's a pseudo in |
523 | the global substitution list. USE must be a dead reference to |
524 | UREGNO in a debug insn. Create a bitmap for DEBUG as needed. */ |
525 | |
526 | void |
527 | dead_debug_add (struct dead_debug_local *debug, df_ref use, unsigned int uregno) |
528 | { |
529 | if (dead_debug_global_replace_temp (global: debug->global, use, uregno, |
530 | pto_rescan: &debug->to_rescan)) |
531 | return; |
532 | |
533 | struct dead_debug_use *newddu = XNEW (struct dead_debug_use); |
534 | |
535 | newddu->use = use; |
536 | newddu->next = debug->head; |
537 | debug->head = newddu; |
538 | |
539 | if (!debug->used) |
540 | debug->used = BITMAP_ALLOC (NULL); |
541 | |
542 | /* ??? If we dealt with split multi-registers below, we should set |
543 | all registers for the used mode in case of hardware |
544 | registers. */ |
545 | bitmap_set_bit (debug->used, uregno); |
546 | } |
547 | |
548 | /* Like lowpart_subreg, but if a subreg is not valid for machine, force |
549 | it anyway - for use in debug insns. */ |
550 | |
551 | static rtx |
552 | debug_lowpart_subreg (machine_mode outer_mode, rtx expr, |
553 | machine_mode inner_mode) |
554 | { |
555 | if (inner_mode == VOIDmode) |
556 | inner_mode = GET_MODE (expr); |
557 | poly_int64 offset = subreg_lowpart_offset (outermode: outer_mode, innermode: inner_mode); |
558 | rtx ret = simplify_gen_subreg (outermode: outer_mode, op: expr, innermode: inner_mode, byte: offset); |
559 | if (ret) |
560 | return ret; |
561 | if (GET_MODE (expr) != VOIDmode) |
562 | return gen_rtx_raw_SUBREG (outer_mode, expr, offset); |
563 | return NULL_RTX; |
564 | } |
565 | |
566 | /* If UREGNO is referenced by any entry in DEBUG, emit a debug insn |
567 | before or after INSN (depending on WHERE), that binds a (possibly |
568 | global) debug temp to the widest-mode use of UREGNO, if WHERE is |
569 | *_WITH_REG, or the value stored in UREGNO by INSN otherwise, and |
570 | replace all uses of UREGNO in DEBUG with uses of the debug temp. |
571 | INSN must be where UREGNO dies, if WHERE is *_BEFORE_*, or where it |
572 | is set otherwise. Return the number of debug insns emitted. */ |
573 | |
574 | int |
575 | dead_debug_insert_temp (struct dead_debug_local *debug, unsigned int uregno, |
576 | rtx_insn *insn, enum debug_temp_where where) |
577 | { |
578 | struct dead_debug_use **tailp = &debug->head; |
579 | struct dead_debug_use *cur; |
580 | struct dead_debug_use *uses = NULL; |
581 | struct dead_debug_use **usesp = &uses; |
582 | rtx reg = NULL_RTX; |
583 | rtx breg; |
584 | rtx dval = NULL_RTX; |
585 | rtx bind; |
586 | bool global; |
587 | |
588 | if (!debug->used) |
589 | return 0; |
590 | |
591 | global = (debug->global && debug->global->used |
592 | && bitmap_bit_p (debug->global->used, uregno)); |
593 | |
594 | if (!global && !bitmap_clear_bit (debug->used, uregno)) |
595 | return 0; |
596 | |
597 | /* Move all uses of uregno from debug->head to uses, setting mode to |
598 | the widest referenced mode. */ |
599 | while ((cur = *tailp)) |
600 | { |
601 | if (DF_REF_REGNO (cur->use) == uregno) |
602 | { |
603 | /* If this loc has been changed e.g. to debug_expr already |
604 | as part of a multi-register use, just drop it. */ |
605 | if (!REG_P (*DF_REF_REAL_LOC (cur->use))) |
606 | { |
607 | *tailp = cur->next; |
608 | XDELETE (cur); |
609 | continue; |
610 | } |
611 | *usesp = cur; |
612 | usesp = &cur->next; |
613 | *tailp = cur->next; |
614 | cur->next = NULL; |
615 | /* "may" rather than "must" because we want (for example) |
616 | N V4SFs to win over plain V4SF even though N might be 1. */ |
617 | rtx candidate = *DF_REF_REAL_LOC (cur->use); |
618 | if (!reg |
619 | || maybe_lt (a: GET_MODE_BITSIZE (GET_MODE (reg)), |
620 | b: GET_MODE_BITSIZE (GET_MODE (candidate)))) |
621 | reg = candidate; |
622 | } |
623 | else |
624 | tailp = &(*tailp)->next; |
625 | } |
626 | |
627 | /* We may have dangling bits in debug->used for registers that were part |
628 | of a multi-register use, one component of which has been reset. */ |
629 | if (reg == NULL) |
630 | { |
631 | gcc_checking_assert (!uses); |
632 | if (!global) |
633 | return 0; |
634 | } |
635 | |
636 | if (global) |
637 | { |
638 | if (!reg) |
639 | reg = regno_reg_rtx[uregno]; |
640 | dead_debug_global_entry *entry |
641 | = dead_debug_global_find (global: debug->global, reg); |
642 | gcc_checking_assert (entry->reg == reg); |
643 | dval = entry->dtemp; |
644 | if (!dval) |
645 | return 0; |
646 | } |
647 | |
648 | gcc_checking_assert (uses || global); |
649 | |
650 | breg = reg; |
651 | /* Recover the expression INSN stores in REG. */ |
652 | if (where == DEBUG_TEMP_BEFORE_WITH_VALUE) |
653 | { |
654 | rtx set = single_set (insn); |
655 | rtx dest, src; |
656 | |
657 | if (set) |
658 | { |
659 | dest = SET_DEST (set); |
660 | src = SET_SRC (set); |
661 | /* Reset uses if the REG-setting insn is a CALL. Asm in |
662 | DEBUG_INSN is never useful, we can't emit debug info for |
663 | that. And for volatile_insn_p, it is actually harmful - |
664 | DEBUG_INSNs shouldn't have any side-effects. */ |
665 | if (GET_CODE (src) == CALL || GET_CODE (src) == ASM_OPERANDS |
666 | || volatile_insn_p (src)) |
667 | set = NULL_RTX; |
668 | } |
669 | |
670 | /* ??? Should we try to extract it from a PARALLEL? */ |
671 | if (!set) |
672 | breg = NULL; |
673 | /* Cool, it's the same REG, we can use SRC. */ |
674 | else if (dest == reg) |
675 | breg = cleanup_auto_inc_dec (src, VOIDmode); |
676 | else if (REG_P (dest)) |
677 | { |
678 | /* Hmm... Something's fishy, we should be setting REG here. */ |
679 | if (REGNO (dest) != REGNO (reg)) |
680 | breg = NULL; |
681 | /* If we're not overwriting all the hardware registers that |
682 | setting REG in its mode would, we won't know what to bind |
683 | the debug temp to. ??? We could bind the debug_expr to a |
684 | CONCAT or PARALLEL with the split multi-registers, and |
685 | replace them as we found the corresponding sets. */ |
686 | else if (REG_NREGS (reg) != REG_NREGS (dest)) |
687 | breg = NULL; |
688 | /* Ok, it's the same (hardware) REG, but with a different |
689 | mode, so SUBREG it. */ |
690 | else |
691 | breg = debug_lowpart_subreg (GET_MODE (reg), |
692 | expr: cleanup_auto_inc_dec (src, VOIDmode), |
693 | GET_MODE (dest)); |
694 | } |
695 | else if (GET_CODE (dest) == SUBREG) |
696 | { |
697 | /* We should be setting REG here. Lose. */ |
698 | if (REGNO (SUBREG_REG (dest)) != REGNO (reg)) |
699 | breg = NULL; |
700 | /* Lose if we're setting something other than the lowpart of |
701 | REG. */ |
702 | else if (!subreg_lowpart_p (dest)) |
703 | breg = NULL; |
704 | /* If we're not overwriting all the hardware registers that |
705 | setting REG in its mode would, we won't know what to bind |
706 | the debug temp to. */ |
707 | else if (REGNO (reg) < FIRST_PSEUDO_REGISTER |
708 | && (REG_NREGS (reg) |
709 | != hard_regno_nregs (REGNO (reg), GET_MODE (dest)))) |
710 | breg = NULL; |
711 | /* Yay, we can use SRC, just adjust its mode. */ |
712 | else |
713 | breg = debug_lowpart_subreg (GET_MODE (reg), |
714 | expr: cleanup_auto_inc_dec (src, VOIDmode), |
715 | GET_MODE (dest)); |
716 | } |
717 | /* Oh well, we're out of luck. */ |
718 | else |
719 | breg = NULL; |
720 | |
721 | /* We couldn't figure out the value stored in REG, so reset all |
722 | of its pending debug uses. */ |
723 | if (!breg) |
724 | { |
725 | dead_debug_reset_uses (debug, head: uses); |
726 | return 0; |
727 | } |
728 | } |
729 | |
730 | /* If there's a single (debug) use of an otherwise unused REG, and |
731 | the debug use is not part of a larger expression, then it |
732 | probably doesn't make sense to introduce a new debug temp. */ |
733 | if (where == DEBUG_TEMP_AFTER_WITH_REG && !uses->next) |
734 | { |
735 | rtx_insn *next = DF_REF_INSN (uses->use); |
736 | |
737 | if (DEBUG_INSN_P (next) && reg == INSN_VAR_LOCATION_LOC (next)) |
738 | { |
739 | XDELETE (uses); |
740 | return 0; |
741 | } |
742 | } |
743 | |
744 | if (!global) |
745 | /* Create DEBUG_EXPR (and DEBUG_EXPR_DECL). */ |
746 | dval = make_debug_expr_from_rtl (reg); |
747 | |
748 | /* Emit a debug bind insn before the insn in which reg dies. */ |
749 | bind = gen_rtx_VAR_LOCATION (GET_MODE (reg), |
750 | DEBUG_EXPR_TREE_DECL (dval), breg, |
751 | VAR_INIT_STATUS_INITIALIZED); |
752 | |
753 | if (where == DEBUG_TEMP_AFTER_WITH_REG |
754 | || where == DEBUG_TEMP_AFTER_WITH_REG_FORCE) |
755 | bind = emit_debug_insn_after (bind, insn); |
756 | else |
757 | bind = emit_debug_insn_before (bind, insn); |
758 | if (debug->to_rescan == NULL) |
759 | debug->to_rescan = BITMAP_ALLOC (NULL); |
760 | bitmap_set_bit (debug->to_rescan, INSN_UID (insn: bind)); |
761 | |
762 | /* Adjust all uses. */ |
763 | while ((cur = uses)) |
764 | { |
765 | if (GET_MODE (*DF_REF_REAL_LOC (cur->use)) == GET_MODE (reg)) |
766 | *DF_REF_REAL_LOC (cur->use) = dval; |
767 | else |
768 | *DF_REF_REAL_LOC (cur->use) |
769 | = debug_lowpart_subreg (GET_MODE (*DF_REF_REAL_LOC (cur->use)), expr: dval, |
770 | GET_MODE (dval)); |
771 | /* ??? Should we simplify subreg of subreg? */ |
772 | bitmap_set_bit (debug->to_rescan, INSN_UID (DF_REF_INSN (cur->use))); |
773 | uses = cur->next; |
774 | XDELETE (cur); |
775 | } |
776 | |
777 | return 1; |
778 | } |
779 | |